The Andes mountains form one of the longest continuous mountain ranges on
Earth, extending from the shores of the Caribbean as far south as the
Magellan Straits. Perhaps the most surprising aspect of this range is how
narrow it is over much of its length - the high part of the range is
typically less than 150 kilometers (93 miles) broad. Illustrated is the
section of the Andes near Coquimbo, Chile, where the highest peaks are
6,300 meters (20,670 feet).
Low lighting and the oblique perspective emphasize the narrowness of the
range, which forms a formidable natural obstacle, and explains how the
improbably long and thin country of Chile acquired its identity.

In this part of the range, active volcanism is absent. The Benioff zone in
this region has a very shallow dip (10°). To both north and south, the
Benioff zone dips more steeply (30°) and volcanism is well developed.
Clouds illuminated by the low sun hang over the Argentine Pampas beyond the
Andes and illustrate the marked climatic differences between different
sides of the Andes. In the south, the Chilean side of the Andes tends to be
well watered and fertile, while the pampas are in rain shadow and tend to
be very dry. Further north, the Chilean coast is exceptionally dry (and
forms the Atacama desert) while the eastern slopes are much wetter.